The ETS PA881 S/PDIF digital audio converter takes signals from Unshielded Twisted Pair (UTP) cable and converts them to coax. Used for temporary setups, as well as in permanent locations where coax is already in place, it's less costly than pulling fresh UTP.
These baluns perform precise impedance-matching and signal balancing, enabling S/PDIP signals to be transmitted with greater signal integrity and longer runs over coaxial cable than can be achieved with UTP wiring.